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采用水热合成法分成铌酸钾钠(KNN),研究了水热起始碱浓度、反应温度以及添加剂种类和浓度对其晶体结构与形貌的影响。研究结果表明:当起始碱浓度比大于或小于1时,KNN晶粒以台阶式生长形成方块晶粒,而碱浓度比接近1时,KNN晶粒细化并大量团聚成球形;当倾向形成富钠型KNN时,铌酸钠长成了纳米棒。当水热反应温度低于200℃时,得到的晶体产物是水热反应的中间产物,经过后续热处理可直接转化为KNN结晶物;添加不同浓度(1~10g/L)的添加剂聚乙二醇400(PEG400)、三乙醇胺、十二烷基苯磺酸钠(SDBS)、乙二胺四乙酸(EDTA)后,均能得到KNN结晶体,但对KNN晶粒形貌影响较大,添加5g/L的PEG400可以抑制晶粒团簇,得到良好分散性且晶体形貌规则的KNN纳米晶颗粒。
Hydrothermal synthesis was used to separate KNN into KNN. The influence of initial hydrotalcite concentration, reaction temperature, additive type and concentration on its crystal structure and morphology was studied. The results show that when the initial alkali concentration ratio is greater than or less than 1, the KNN grains grow in a stepwise manner to form square grains. When the alkali concentration ratio is close to 1, the KNN grains are refined and agglomerated into a large number of spheres. When sodium-rich KNN is used, sodium niobate grows into nanorods. When the hydrothermal reaction temperature is lower than 200 ℃, the obtained crystal product is the intermediate product of hydrothermal reaction, which can be transformed into KNN crystallites directly after the subsequent heat treatment. Adding different concentrations of polyethylene glycol (1 ~ 10g / L) KNN crystals can be obtained after 400 (PEG400), triethanolamine, sodium dodecyl benzene sulfonate (SDBS) and ethylenediaminetetraacetic acid (EDTA), but have a great influence on the grain morphology of KNN. L PEG400 can inhibit the grain clusters, to obtain well-dispersed KNN nanocrystalline particles with regular crystal morphology.